Doctor Strange was confirmed as part of Phase 3 by Kevin Feige himself.

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Could the oft-rumored "Doctor Strange" be a part of those plans?

"'Doctor Strange,' which I've been talking about for years, is definitely one of them," he confirmed. "He's a great, original character, and he checks the box off this criteria that I have: he's totally different from anything else we have, just like 'Guardians of the Galaxy.' He's totally different from anything we've done before, as is 'Ant-Man,' which keeps us excited."